#!/usr/bin/env python
# encoding: utf-8
# @author: Lin Han
# @contact: voldemort22@126.com
# @file: interview_answer.py
# @time: 2021/5/17 17:09
# @desc:
def step(n):
    if n in (1, 2):
        return n
    return step(n - 2) + step(n - 1)

# def flower(data, n):
#     res = 0
#     data_len = len(data)
#     for i in range(data_len):
#         if i == 0:
#             if data[i] == 0 and data[i + 1] == 0:
#                 n -= 1
#                 data[i] = 1
#             if data[i] == (data_len - 1):


if __name__ == '__main__':
    print(step(2))
